4.  The applicants were both born in 1952 and live in Gießen.
5.  The facts of the case, as submitted by the parties, may be summarised as follows.
6.  In September 1997 the applicants and their neighbour filed a request with the Gießen administrative authorities (“the administration”) seeking permission to cut down their neighbour’s tree which, according to an expert opinion obtained by the applicants, was causing damage to their house.
7.  On 19 November 1997 the administration rejected this request. On 9 March 1998, on the applicants’ administrative appeal, the administration granted permission to cut down the tree on the ground that they could not exclude the possibility that the damage to the house had been caused by the tree.
8.  Subsequently, the applicants’ neighbour refused to cut down the tree.
9.  In August 1998 the applicants requested the Gießen Regional Court to order their neighbour to cut down the tree.
10.  On 23 November 1998, following submissions by the defendant, who also presented an expert report, the court decided to obtain an expert opinion from a Dr Str. On 30 January 1999 Dr Str. submitted his report.
11.  On 3 May 1999, following a hearing, the Gießen Regional Court decided that the applicants’ neighbour had to cut down the tree or take other measures to prevent the earth from drying out.
12.  On 29 June 1999 the applicants’ neighbour appealed. She also submitted another expert opinion.
13.  On 28 July 1999 the Frankfurt/Main Court of Appeal, on provision of a security by the neighbour, stayed the proceedings for enforcement of the first-instance judgment. Subsequently, the case was transferred to a single judge.
14.  On 9 August 1999 the court scheduled a hearing for 12 November 1999. That day it decided to obtain an expert opinion. On 10 January 2000 it commissioned Professor K., an expert on construction matters.
15.  On 11 January 2000 the applicants lodged a subsequent appeal (Anschlussberufung).
16.  On 2 February 2000 the court amended its decision regarding the taking of evidence. Subsequently, it also requested a further advance. On 26 March 2000 the applicants paid the requisite advance. A few days later they questioned the expert’s qualification. On 26 April 2000 the court sent the files to the expert.
17.  On 25 August 2000, following comments made by the expert about the applicants’ objections against him, the court mandated Professor K. to proceed with the report. On 22 September 2000 Professor K. informed the court about the cost of his services (which amounted to about 25,000 euros (EUR)).
18.  In November 2000 the court requested the files from the expert and on 9 February 2001, on appeal by the defendant, it quashed a decision of the Gießen Regional Court concerning the enforcement proceedings.
19.  On 23 February 2001 the court proposed to the applicants that, in view of the exceptionally high costs claimed by Professor K., evidence should be taken by other means and proposed a Dr S., a landscaping expert.
20.  On 12 March 2001 the applicants opposed the proposal since, in their view, Professor K.’s report was indispensable. They also opposed the choice of Dr S. on the grounds that he had been proposed by the defendant, knew the defendant’s son and it could be assumed that he had been talking with him about the case.
21.  At the subsequent hearing on 20 April 2001 the applicants requested Dr S. to declare that he did not have any personal ties with the defendant or her son and had not dealt with the case before. On 29 June 2001, following this declaration by Dr S., the court commissioned Dr S. to provide an expert opinion.
22.  On 4 November 2001 the court asked the applicants to comment on a statement by Dr S. dated 6 August 2001. In December 2001 the expert requested a further advance. On 11 July 2002 he submitted his report. He came to the conclusion that the tree had not caused the damage to the house.
23.  On 29 August 2002, following the applicants’ submissions, the court asked Dr S. and the first-instance expert, on condition of the payment of a further advance, to explain and supplement their reports. In October 2002 it amended its decision; in November 2002 it requested a further advance. On 20 January 2003 it transferred the files to Dr S.
24.  In April 2003 the court requested a further advance of EUR 500 from both parties. On 1 August 2003, at the request of the applicants, it further amended the order regarding the taking of evidence. On 29 August 2003 the defendant paid the advance. The court then requested the expert to continue with his report.
25.  In June 2004 Dr S. submitted his supplementary report. The court then transferred the files to the parties for further submissions.
26.  On 23 June 2004 the applicants requested the court to transfer the case from the single judge to a bench.
27.  On 2 September 2004 the court scheduled a hearing for 6 October 2004. It later had to be postponed to 3 November 2004 owing to the absence of the parties’ legal counsels. At the hearing, the court (again composed of three judges) established that a report by a construction expert was necessary in order to reach a decision. It also encouraged the parties to reach a friendly settlement in view of the high costs claimed by Professor K. None of the experts were summoned.
28.  On 22 December 2004 the court decided that, in view of the additional submissions, further evidence should be obtained by Dr S. as regards the position of the roots of the tree. It also requested an advance of EUR 2,000.
29.  In February 2005 the applicants asked the court to amend this decision. This however was rejected in March 2005 and again later on a renewed request. In April 2005 the court confirmed that the applicants had already paid the advance (requested again in March) on 5 January 2005.
30.  On 19 October 2005 a local inspection took place.
31.  By a letter dated 21 January 2006 the applicants lodged a constitutional complaint on account of the length of the proceedings. On 9 February 2006 the Federal Constitutional Court refused to accept the constitutional complaint for adjudication. It found that there was no indication of a violation of the applicants’ rights.
32.  On 20 March 2006 the Court of Appeal requested another advance of EUR 28,500. In June 2006 it again refused to amend its decision regarding the taking of evidence; also in June 2006 the applicants paid the advance.
33.  On 10 October 2006 the expert informed the parties that the local inspection (which required free access to the applicants’ cellar) should take place on 9 November 2006. At the applicants’ request, it was postponed to 22 January 2007.
34.  On 20 February 2007 the expert submitted an interim report; on 12 July 2007 he submitted his final report.
35.  On 14 September 2007 the court scheduled the hearing. On 19 December 2007 the Frankfurt/Main Court of Appeal ordered the neighbour to cut down the tree.